We have three kinds of material as the working substance:Kerosene/Mercury/Alcohol,each substance has different boiling point and freezing point.
Its boiling point is generally higher than 150 ℃, freezing point is lower than - 30 ℃. So the measuring range of kerosene thermometer is about - 30 ~150 ℃. Kerosene thermometers above 150 degrees are non-standard.
General Standard Kerosene Temperature Measurement Range: - 30-100 ℃; 0-50 ℃; 0-100 ℃; 0-150 ℃.
Mercury thermometer is a kind of expansive thermometer. The freezing point of mercury is -39 ℃ , the boiling point is 356.7 ℃. It is used to measure the temperature in the range of -39 ℃-357 ℃.
General Standard Mercury Temperature Measurement Range: - 30-100 ℃ (30cm full length,Min Scale:1 ℃); 0-50 ℃(30cm full length,Min Scale:0.2 ℃/(45cm full length,Min Scale:0.1 ℃); 0-100 ℃/(45cm full length,Min Scale:0.2 ℃); 100-200 ℃(45cm full length,Min Scale:0.2 ℃); 200-300 ℃(45cm full length,Min Scale:0.2 ℃).
The boiling point of alcohol is 78 ℃ and the freezing point is - 117 ℃. The temperature of alcohol thermometer is lower than that of kerosene thermometer.
General standard alcohol thermometer Measurement Range: -50-50 ℃;-80-60 ℃;-100-40 ℃;Full Length:30mm;Min Scale:1 ℃
How to choose the suitable liquid thermometer?
The user should choose the thermometer according to his general working temperature.Compared with mercury thermometer,Kerosene thermometer is rather safe,and the red scale makes reading more easily ,and it is cheaper than mercusy thermometer.If the working temperature is always low,alchohl thermometer seems have more advantages.When measuring the body temperature of animals orhuman bodies,the thermometer has more higher accuracy.